Axle guide

ABSTRACT

The invention relates to an axle guide consisting of a fibre-synthetic material composite for guiding an axle in the running gear of a rail vehicle, in particular a high-speed rail vehicle. Said guide has two end sections ( 11, 11 ′) for connecting the guide ( 1 ) both to the axle and to the chassis ( 2 ) of the running gear in a manner resistant to torsion and a central section ( 12 ) located therebetween, which has a longitudinal axis ( 13 ) aligned with the direction of travel (X) and across-section that is at least partially flat in the vertical direction (Z). The guide ( 1 ) has at least one integrated flexural joint ( 14 ) with a vertical flexural axis ( 15 ) and enables a rotational degree of freedom, which protects the wheel beating from damaging flexural stresses, to be achieved simply without the need for an additional joint component. The inventive guide also benefits from all the advantages of the glass fibre-synthetic material composite, such as adjustable rigidity that can be reproduced with narrow tolerances and that is defined almost independently of the temperature, resistance to wear, electric insulation, excellent material damping properties and favourable behaviour if a malfunction occurs.

[0001] The invention relates to an axle guide consisting of afibre-synthetic material composite for guiding an wheelset in therunning gear of a rail vehicle, according to the precharacterising partof claim 1.

[0002] High-speed rail traffic places particularly stringent demands onthe running gears of rail vehicles. The components of wheelset guidancein high-speed trains are subjected to particularly high loads. They haveto ensure safe travel of the rail vehicle, day in day out, over severalyears, experiencing little wear in operation while at the same timerequiring little maintenance. The linking of the wheelsets to therunning gear chassis is decisive as far as safety and comfort areconcerned. The wheelset guides in the running gear of rail vehiclesserve the purpose of linking the axles to the running gear chassis, bothin the direction of travel and transversely to it. In this context, thedynamics of the train require wheelset guide rigidities within a narrowtolerance band. The vertical rigidity of a wheelset guide should be veryslight, so as to have as little influence as possible on primaryspringing. Thus, vertical rigidity is to be attuned with regard to itsspring rate. Precisely and permanently meeting the required specifiedtransverse rigidity is of prime importance for the desired dynamiccharacteristics of the train to remain within narrow boundaries. Forhigh-speed travel, longitudinal rigidity must be as high as possible.Nevertheless, low-wear operation makes a certain compliance in thelongitudinal direction desirable, so that in curved sections of thetrack the wheelsets can better adapt to the different radii of the twocurved rails, thus reducing frictional wear on the wheels. To avoidcurrent-induced damage to the wheelset rolling bearings, it is desirablefor the wheelset guides to comprise a material which is not electricallyconductive, or for the wheelset guides to be held to the wheelset in anon-conductive manner. For reasons of comfort, they should also havegood damping properties so as to largely prevent the transmission ofstructure-borne noise from the wheelset to the running gear, and thus tothe vehicle body.

[0003] From EP 0 363 573 A2, a wheelset guide with a fibre compositecomponent for the bogie of a rail vehicle is known, which for thepurpose of guiding the wheelset axles is leaf-spring-shaped. In order totransmit transverse moments, the wheelset guide is attached at endsections so as to be form locked and force locked, both to the wheelsetbearing housing and to the bogie frame. The central section of the fibrecomposite component, extending along a horizontal longitudinal axis ofthe component, is of constant cross section which is flat in thevertical direction, in the manner of a leaf spring. In this way, thefibre composite component of the wheelset guide provides flexuralelasticity in the vertical direction, while being highly rigid bothtransversely and longitudinally. This known wheelset guide has norotational degree of freedom between the wheelset guide and the bearinghousing, and, consequently, the wheel bearing housing is subjected to anundesirable flexural stress which in particular in the case ofhigh-speed rail vehicles is very considerable.

[0004] It is thus the object of the invention to create a wheelset guideof the type mentioned in the introduction which provides for arotational degree of freedom between the wheelset guide and the housingof the wheel bearing.

[0005] According to the invention, this object is met by a wheelsetguide according to the preamble of claim 1, in which the wheelset guide,preferably in its central section, comprises at least one integratedflexural joint with vertical flexural axis. Depending on therequirements, two or several flexural joints, spaced apart from eachother and comprising vertical flexural axes, may be provided.Preferably, the wheelset guide according to the invention comprises onlyone such flexural joint. In this way, a rotational degree of freedombetween the wheelset guide and the wheel bearing housing is achievedwithout the need to attach an additional joint of differential design.Depending on the requirements, the flexural joint can be located in anyposition along the longitudinal extension of the wheelset guide. Thedesign of the wheelset guide according to the invention as asingle-piece fibre-synthetic material composite component makes itpossible to set the rigidities of the wheelset guide in a targeted wayvia the geometry. In this way, connection of the wheelsets to therunning gear frame can be established with a rigidity that can bereproduced within narrow tolerances, and that is almost independent ofthe temperature. This in turn makes it possible to increase the speed oftravel while providing a high degree of safety and little wheel wear.The wheelset guide can be designed such that for the duration of theuseful life of the rail vehicle it can be considered to be serviceable,and in contrast to wheelset guides whose rotational degree of freedom isachieved by means of a rubber bush, said wheelset guide is resistant towear, without the need for continual maintenance or even replacement atregular intervals. By using a glass fibre synthetic material composite,desirable electrical insulation is achieved to prevent current-relateddamage to the rolling bearings of the wheelsets. When compared to steel,fibre-synthetic material composite has significantly better materialdamping properties. Consequently, the wheelset guide according to theinvention to a very large extent prevents structure-borne noise from thewheelset to the running gear, and thus to the body; in this wayincreasing passenger comfort.

[0006] In a preferred embodiment of the invention, in particular thecentral section of the wheelset guide comprises a sub-section whosecross-section tapers off towards the flexural joint. In this way, theeffect of flexibility in the vertical direction is enhanced.Tapering-off of the cross-section may take place along the longitudinalaxis of the wheelset guide, corresponding to the distribution of thebending moment, by a gradual narrowing of the horizontal width. Inaddition or as an alternative, it is also possible to gradually reducethe vertical thickness of the cross-section in the direction towards theflexural joint.

[0007] In an advantageous embodiment of the invention, the flexuraljoint is arranged between two sub-sections with cross-sections whichtaper off in opposite directions. In this embodiment, the flexural jointis preferably placed in the middle of the wheelset guide. In thisconfiguration, the axle guide is symmetrically deformed in anadvantageous way, both during vertical load transmission in a S-shapeand during horizontal transverse load in a V-shape.

[0008] In a preferred embodiment of the invention, the flexural joint isa horizontal throat in the cross-section of the wheelset guide. By wayof this throat in the cross-section of the wheelset guide, a region ofincreased flexibility around a vertical axis and thus a flexural jointwith vertical flexural axis is integrated in the wheelset guide in aparticularly simple way.

[0009] In a particularly preferred embodiment of the invention, thecross-section of the wheelset guide, in the region of the flexuraljoint, is at least partly flat in horizontal transverse direction. Inthis way, an additional cross-sectional area which extends in verticaldirection can be added to the cross-section of the horizontally throatedflexural joint so as to reduce the danger of buckling in the region ofthe joint when transmitting longitudinal forces.

[0010] Preferably, a glass fibre synthetic material composite withfibres predominantly extending in the direction of the longitudinal axisof the wheelset guide is provided as a material for the wheelset guide.This material, for example with E-glass fibres, is particularly suitablebecause it provides very high fatigue resistance at low rigidity. Thedifferent requirements for rigidity in various spatial directions aremet by way of aligning the direction of the fibres.

[0011] In an advantageous embodiment of the invention, the centralsection of the wheelset guide comprises shearing-action bearing layerswith fibres crossing each other, in a horizontal plane, at an angle of±50 to ±60° in relation to the longitudinal axis. In such a case it isfavourable to place the flexural joint in the middle of the wheelsetguide and design the size of the cross-section so that it is adequate toprevent stability failure as a result of buckling. Consequently, thewheelset guide can also take very considerable pressure forces which actin longitudinal direction.

[0012] In a further advantageous embodiment of the invention, the endsections of the wheelset guide predominantly comprise fibres whichextend unidirectionally in the direction of the longitudinal axis, whilethe central section predominantly comprises fibres crossing each other,in a vertical plane, at an angle of ±5° to ±60° in relation to thelongitudinal axis. This measure also strengthens the central section ofthe wheelset guide so that it shows improved vertical flexural rigidity.

[0013] Preferably, the vertical flexural rigidity of the wheelset guideis higher in the region of the flexural joint than it is in other axleguide regions. In this way, the flexural joint may be designed with acorrespondingly reduced cross-section, i.e. it may for example have amore pronounced throat in the horizontal transverse direction.

[0014] In a further particularly preferred embodiment of the invention,at least one closed torsion tube made of fibre layers with fibresintersecting at an angle of ±5° to ±60° in relation to the longitudinalaxis is arranged in the core of the wheelset guide. In addition, outsidethe core, the wheelset guide comprises fibres which predominantly extendin the direction of the longitudinal axis. The inclusion of a tube inthe cross-section of the axle guide not only improves the transverse andlongitudinal rigidity but also the torsional stiffness around thelongitudinal axis of the wheelset guide, thus improving the loadingcapacity and the integrity of the wheelset guide overall.

[0015] In a further particularly preferred embodiment of the invention,the core of the axle guide comprises high-strength R-glass fibres orS-glass fibres or high-strength or highly-rigid carbon fibres rightthrough from one end section to the other end section. With E-glassfibres preferably used otherwise, this measure particularly strengthensthe cross-section of the wheelset guide by replacing the glass fibreswith high-strength or highly rigid fibres particularly againstlongitudinal tensile forces or pressure forces.

[0016] In another preferred embodiment of the invention, the endsections comprise wedge-shaped thickened sections. In this way, theintroduction of force against the wheelset guide being pulled out fromthe clamping arrangement on the side of the frame or of the bearing isadditionally supported by form locking. According to an alternativeembodiment of the invention, the end sections comprise fixing lugs. Forexample, a double lug connection is eminently suitable for takinglateral forces for moment-resistant attachment of the wheelset guide tothe wheelset and to the running gear frame.

[0017] Below, further advantageous embodiments of the invention aredescribed by means of an embodiment, shown in the drawing, of a wheelsetguide according to the invention. The following are shown:

[0018]FIG. 1 a wheelset guide according to the invention, in itsinstallation environment;

[0019]FIG. 2 a perspective view of an embodiment of a wheelset guideaccording to the invention; and

[0020]FIG. 3 an end section of a wheelset guide according to theinvention, of an embodiment differing from that shown in FIG. 2.

[0021] According to FIG. 1, for the purpose of guiding a wheelset, eachside of the running gear or bogie of a rail vehicle, said running gearor bogie comprises two wheelset guides 1, arranged in parallel with oneon top of the other, and with said wheelset guides 1 being connectedboth to the frame 2 of the running gear and to the housing 3 of thewheel bearing. The axles of the wheels 4 of the wheelset are held in thewheel bearings, which are rolling bearings. The frame 2 is supported onthe wheelset by way of a primary spring 5, which is a helical spring. Anoscillation damper 6 is arranged parallel to the primary spring 5, bothtogether characterising the vertical spring movement of the frame 2relative to the wheelset of the rail vehicle. Parallel arrangement ofthe wheelset guides 1 provides the advantage that additional flexuralstress of the primary spring 5 is avoided. The wheelset guides areclamped at the ends so as to be resistant to torsion. The tension forcesare applied by way of straining rings 7 made of fibre compositematerial, and acting on the ends of the two wheelset guides 1 arrangedone on top of the other. By means of threaded connections 9, thewheelset guides 1 are clamped via steel blocks 8, which are arranged inthe middle between said wheelset guides 1, to the housing 3 of the wheelbearing, and, by way of a bracket 10, to the frame 2 of the runninggear. During parallelly guided lowering of one of the two wheelset guideclamping arrangements, an S-shaped deformation of the entire wheelsetguide 1 results. The longitudinal axis of the wheelset guides 1 isaligned approximately in the direction of travel X. Except for thesection right in the middle, the cross-section is flat in the verticaldirection Z, because the wheelset guide 1 should be as flexible aspossible in the direction of the spring deflection of the carriage.

[0022] According to FIG. 2, the axle guide 1 comprises two end regions11 and 11′ for connection to the wheelset and the frame 2 of the runninggear, as well as a central section 12, arranged in-between. A flexuraljoint 14 comprising a flexural axis 15 which extends in the verticaldirection Z is arranged in the central section 12 with respect to thelongitudinal axis 13 of the wheelset guide 1, with said longitudinalaxis 13 being aligned parallel to the direction of travel X. Theflexural joint 14 comprises a horizontal throat 16 with a cross-sectionwhich is flattened in the horizontal transverse direction Y. Thisprovides for the flexibility which is required around the flexural axis15, in the region of the flexural joint 14, while at the same timeproviding for a cross-section extending in the X-Z plane, of adequatesize to provide very good longitudinal rigidity of the wheelset guide 1.On both sides of the flexural joint 14, in the longitudinal direction13, sub sections 17 and 17′ follow, wherein the cross-section of thewheelset guide 1 tapers off towards the direction of the flexural joint14. This tapering-off of the cross section is achieved by a componentthickness which is reduced both in the Z-direction and in theY-direction, said reduction corresponding to the flexural momentsencountered during operation. The end sections 11 and 11′ comprisewedge-shaped thickened sections 18 and 18′, so that torsion-resistantclamping of the axle guide 1 is not only achieved by a frictionalconnection due to the straining ring, but also by a form lockingconnection.

[0023] As an alternative, according to FIG. 3, the end region 11 of theaxle guide 1 can comprise two fixing lugs 19. This double lug connectionis particularly well suited to taking transverse forces or lateralforces and the resulting moments of flexion.

1. A wheelset guide made of a fibre-synthetic material composite forguiding a wheelset in the running gear of a rail vehicle, in particulara high-speed rail vehicle, comprising two end sections (11, 11′) forconnecting the wheelset guide (1) both to the wheelset and to the frame(2) of the running gear in a manner resistant to torsion, and a centralsection (12) located in between, having a longitudinal axis (13)approximately aligned with the direction of travel (X) and across-section that is at least partially flat in the vertical direction(Z), characterised in that the wheelset guide (1) comprises at least oneintegrated flexural joint (14) with a vertical flexural axis (15). 2.The wheelset guide according to claim 1, characterised in that thecentral section (12) comprises at least one sub-section (17, 17′) whosecross-section tapers off towards the flexural joint (14).
 3. Thewheelset guide according to claim 1 or 2, characterised in that theflexural joint (14) is arranged between two sub-sections (17, 17′) withcross-sections tapering off in opposite directions.
 4. The wheelsetguide according to any one of claims 1 to 3, characterised in that theflexural joint (14) is a horizontal throat (16) in the cross-section ofthe wheelset guide.
 5. The wheelset guide according to any one of claims1 to 4, characterised in that the cross-section of the wheelset guide(1), in the region of the flexural joint (14), is at least partly flatin a horizontal transverse direction (Y).
 6. The wheelset guideaccording to any one of claims 1 to 5, characterised in that a glassfibre synthetic material composite with fibres predominantly extendingunidirectionally in the direction of the longitudinal axis (13) isprovided as a material for the wheelset guide (1).
 7. The wheelset guideaccording to any one of claims 1 to 6, characterised in that the centralsection (12) of the wheelset guide (1) comprises shearing-action takinglayers with fibres crossing each other at an angle of ±50 to ±60° inrelation to the longitudinal axis (13).
 8. The wheelset guide accordingto any one of claims 1 to 7, characterised in that the end sections (11,11′) of the wheelset guide (1) predominantly comprise fibres extendingunidirectionally in the direction of the longitudinal axis (13), and inthat the central section (12) predominantly comprises fibres crossingeach other at an angle of ±5° to ±60° in relation to the longitudinalaxis (13).
 9. The wheelset guide according to any one of claims 1 to 8,characterised in that the vertical flexural rigidity of the wheelsetguide (1) is higher in the region of the flexural joint (14) than it isin other wheelset guide regions.
 10. The wheelset guide according to anyone of claims 1 to 9, characterised in that at least one closed torsiontube made of fibre layers with fibres intersecting at an angle of ±5° to±60° in relation to the longitudinal axis (13) is arranged in the coreof the wheelset guide (1), and in that, outside the core, the wheelsetguide (1) comprises fibres predominantly extending in the direction ofthe longitudinal axis (13).
 11. The wheelset guide according to any oneof claims 1 to 10, characterised in that the core of the wheelset guide(1) comprises high-tensile R-glass fibres or S-glass fibres orhigh-strength or highly-rigid carbon fibres right through from one endsection (11) to the other end section (11′).
 12. The wheelset guideaccording to any one of claims 1 to 11, characterised in that the endsections (11, 11′) comprise wedge-shaped thickened sections (18, 18′).13. The wheelset guide according to any one of claims 1 to 12,characterised in that the end sections (11) comprise fixing lugs (19).